Inhabitants of Harad.
Tolkien's portrayal of the Haradrim is open to criticism for racism - at one point he describes them as looking like trolls because they are black. However, it should be noted that the Haradrim are typically cajoled into combat by evil Numenoreans, who are white - effectively parallelling the use of colonial troops in European armies.
The name "Haradrim" means "people of the south" in elvish. Also known as Southrons (although these are rendered as a separate people in some accounts).
The Haradrim fought on the side of Sauron in the Lord of the Rings.